It looks like you have a long term project, and you have a yard. Good combo. Plan on 10+ years with this guy before he's even in a pot. (Sorry)
Don't bare root entirely, but take him out of the pot and prune off about half the depth of the roots this year. Put him back in the pot after you have raised the pot's soil level enough to have the tree's base stick a few inches above the edge of the pot - the rains and watering will gradually wear the surface soil away so you can see the surface roots/nebari. Chopsticks will allow you to scape some away as well. Fertilize well this year.
Next early spring, take him out of the pot again, and try to root prune off any large or deep roots, and use a root hook or chopstick to disentangle and partially desoil the root ball further. Plant him in the ground in your yard. Plant him at a slant, at least a small one, unless you want to go for a formal upright (I wouldn't try).
Then, when it is dormant the next winter, chop the whole thing up just below that large healthy whorl. The next spring it will start to put all its energy into the few small branches that sit down low - those will form your future tree. Learn what to do from there from Brent's blog at Evergreen Gardenworks, or Stone Lantern's Pine book.
Good luck and enjoy.